Micrometer attachment for machinists&#39; calipers.



J. H. PEMBER.

MIGROMETER ATTACHMENT FOB. MAGHINISTS CALIPERS.

APPLICATION FILED NOV. 15,' 1909.

Patented June 28, 1910.

LVV/ENTOR.

- P are (10) JOHN PEMBER, OF COLUMBUS, OHIO.

MICROMETER ATTACHMENT FOR M ACHINISTS CLIPEBS.

Specication of Letters Patent.

atented June 2S, 1910.

Application led November 15, 1909. Serial No. 528,191.

To all whom 'it may concern:

Be it known that 1, JOHN H. PEMBER, a citizen of the United States, residing at Columbus, in the county of Franklin and State of Ohio, have invented a new and useful Micrometer Attachment for Machinists Calipers, of which the following is a specication.

My invention relates to a new and useful improvement in calipers, for the use of machinists or shop inspectors, and relates particularly to an attachment adapted to be clamped to one leg of a machinists caliper whereby minute variations from a predetermined standard may be detected. I attain this object by the device hereinafter fully described reference being had t0 the accompanying drawing, in which- Figure 1 is yaront view of the attachment partly in section, Fig. 2 a side view, Fig. 3 shows the attachment applied to an inside caliper and Fig. 4 shows it applied to an outside caliper.

Like numerals refer to similar parts in the several figures.

At the lower end of a bar (1) and extending at right angles thereto is a cylinder (2) in which slides a piston (3)\having a head (4) held yieldingly in contact with a shoulder (5) -by the short arm (6) of a lever pivoted 'at y(7) and actuated by the spring (8). f'f' ng arm of said lever is extended to fori ointer (9) traversing a graduated to indicate movements of the piston (3).

Formed in the wall of the .cylinder is a recess (11) adapted to engage the point (12) oflone leg of a caliper 13) while the bar (14) and clamping screws (14a) hold the attachment in place. A guard (15) serves to protect the pointer (9) and limit its travel. f

As constructed for ordinary shop use the 'piston (3) is about one-tenth of an inch longer than the cylinder (2) and the proportlons of the lever arms are such that a movement of the piston of live one-hundredths of an inch causes the pointer (9) to traverse the entire length of the arc which is graduated to indicate movements of the pisvton of thousandths of an inch, zero being the center of the scale.

.It is used as ollows:-The caliper is opened to approximately the. dimension which is to be tested, the leg (13) inserted between the bar (14) and the graduated arc (10), the point 12) inserted in the recess 11 the bar (1 rotated about the point 1,2) until the axis of the piston (3) is in a straight line with the op osito olnt (16) and the clamping screws 149') tlghtened to hold the attachment in place, the caliper is then ap lied to a standard gage and its width adjusted by means of the adjusting' screws (17) until the pointer (9)' stands at zero. When the caliper is applied to the piece which vis to be tested the ointer will come to zero if its diameter con orms to the gage, any variation therefrom, either larger or smaller, being indicated in thousandths of an inch within range of the instrument.

What I claim as novel and desire to secure by Letters Patent is 1. An attachment for a cali er consisting of a body portion having a cy indrical portion, a recess therein ada ted to receive the point of lone leg of the ca iper in such manner as to allow rotation of said body portion about said point to aline the central axis of said cylinder with the oppositepoint of the caliper, a clamp to secure the body portion against rotation, a piston capable of longitudinal movement within the cylinder, a spring tending to move said piston, a head limiting said movement, and a pointer ind1- eating on a graduated are the movements of said piston, substantially as set forth.

2. An indicator of the spring actuated piston type having a recess adapted to receive the point of one leg of a caliper in such manner that the indicator may be rotated about said point tocorrect the alinement of the piston with the opposite point of the caliper and a clamp to secure the indicator against rotation, substantiall as set forth.

In testimony whereof I a x my signature in presence of two witnesses.

JOHN u. PEMBEB.

Witnesses:

Downs SGHAAF, S. H. CABMAox. 

